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What are primordial black holes? · Daniel and Kelly’s Extraordinary Universe

• 0:08
  Speaker 1: Hey, Daniel, you believe in the power of words, right,
• 0:11
  Speaker 1: I hope words have power. I mean this podcast is
• 0:14
  Speaker 1: literally just words. It's our superpower. Yeah. But also, don't
• 0:18
  Speaker 1: you think individual words have a certain energy to them?
• 0:21
  Speaker 1: You know? I think some words are just like inherently funny,
• 0:23
  Speaker 1: you know, words like booger or weasel or podcast. Yeah,
• 0:27
  Speaker 1: those are goofy words. But some words have drama to them,
• 0:31
  Speaker 1: you know, like dragon or chaos. And the combination there
• 0:34
  Speaker 1: makes me think of things like dragon boogers or chaos
• 0:37
  Speaker 1: weasels a soul. I was thinking more like dragon weasels.
• 0:40
  Speaker 1: That's a scary word. I don't know if that's scary
• 0:44
  Speaker 1: or silly. But what about some science words? You think
• 0:46
  Speaker 1: some science words have power to them? I don't know.
• 0:48
  Speaker 1: I feel like this is a trap. You're always making
• 0:50
  Speaker 1: fun of our science names, you know, charm, cork, big bang,
• 0:54
  Speaker 1: those are charming words, indeed, But I mean, can you
• 0:57
  Speaker 1: blame me? Do you guys ever come up with dramatic
• 0:59
  Speaker 1: names wol names? I got something up my sleeve. We've
• 1:02
  Speaker 1: got something out of the dawn of time. All right,
• 1:05
  Speaker 1: this better be good? Oh? Yes, it is positively primordial.
• 1:24
  Speaker 1: I am Morehammad cartoonists and the creator of PhD Comics. Hi,
• 1:28
  Speaker 1: I'm Daniel. I'm a particle physicist, and I believe in
• 1:31
  Speaker 1: the power of words to entertain and educate. Welcome to
• 1:35
  Speaker 1: our podcast, Dragon Boogers, brought to you by two podcasting
• 1:40
  Speaker 1: Chaos Weasels. I'm just kidding. Welcome to our podcast Daniel
• 1:44
  Speaker 1: and Jorge Explain the Universe, a production of I Heart
• 1:47
  Speaker 1: Radio in which we use words to take you on
• 1:50
  Speaker 1: a mental tour of the universe. We take you all
• 1:53
  Speaker 1: the way back to the beginning of time, we take
• 1:55
  Speaker 1: you to the edge of time. We take you down
• 1:57
  Speaker 1: to the tiny particles and out to the largest things
• 2:00
  Speaker 1: in the universe, and we share with you our wonder,
• 2:03
  Speaker 1: our joy, our curiosity for how everything works and what
• 2:07
  Speaker 1: science is doing to try to figure it out today. Yeah,
• 2:10
  Speaker 1: it goes straight from our brains and our hearts through
• 2:12
  Speaker 1: the Internet into your ears, and straight into your brains
• 2:15
  Speaker 1: and hopefully your hearts as well. That's right through that
• 2:17
  Speaker 1: weird system of tubes that is the Internet. We should
• 2:20
  Speaker 1: we should talk about that one day, Daniel Jorge explained
• 2:23
  Speaker 1: the tubes. But there are a lot of amazing things
• 2:26
  Speaker 1: out there in the universe. To see and to discover
• 2:28
  Speaker 1: and to learn about. And some of those things have
• 2:31
  Speaker 1: been around for a very long time. I mean, the
• 2:34
  Speaker 1: universe is it's pretty old or maybe pretty young, depending
• 2:37
  Speaker 1: on how you look at it, that's right, And there
• 2:39
  Speaker 1: are a lot of amazing things out there to understand. Stars,
• 2:41
  Speaker 1: exploding stars, collapsing, black holes forming. Some of these things
• 2:45
  Speaker 1: that you're already amazed by might have a very different
• 2:48
  Speaker 1: history from the one that your anticipated, Yeah, because I
• 2:51
  Speaker 1: think sometimes knowing the history or something gives you a
• 2:53
  Speaker 1: better perspective about it, you know, like if you know
• 2:55
  Speaker 1: where it came from or or what it was like before,
• 2:59
  Speaker 1: it kind of tells a lot about something. Yeah. Well,
• 3:01
  Speaker 1: that's basically the whole game of astrophysics, right. We are
• 3:03
  Speaker 1: looking at the universe, which is nothing but a series
• 3:06
  Speaker 1: of clues as to how the universe was made, and
• 3:09
  Speaker 1: from that set of clues, we try to unravel the
• 3:11
  Speaker 1: mystery of what came first and what came second, and
• 3:14
  Speaker 1: what does that mean about what's coming next? Right, So
• 3:17
  Speaker 1: the history of like how things were put together is
• 3:19
  Speaker 1: really central to all of science and all certainly all
• 3:22
  Speaker 1: of astrophysics, and I think one of the things that
• 3:24
  Speaker 1: fascinated most people about the universe is this idea of
• 3:28
  Speaker 1: black holes. I mean, black holes are just kind of amazing,
• 3:31
  Speaker 1: aren't Then there's so it's so weird and so kind
• 3:34
  Speaker 1: of a mysterious I know, and in so many ways.
• 3:37
  Speaker 1: You know, you have the fact that they first started
• 3:39
  Speaker 1: as a theoretical idea, like just a solution to equations
• 3:43
  Speaker 1: and pencil and paper. The idea that just this concept
• 3:47
  Speaker 1: is scratching of graphite on paper could predict crazy things
• 3:51
  Speaker 1: happening out there in the universe. That's mind blowing. And
• 3:54
  Speaker 1: then you know the drama in which they are formed,
• 3:56
  Speaker 1: the end of the life of a star, this cataclysmic laps,
• 4:00
  Speaker 1: the supernova, the precede to them. I mean, you couldn't
• 4:03
  Speaker 1: write anything better than that if you were fiction right now. Yeah,
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  Speaker 1: there's there was drama in how they were discovered and
• 4:08
  Speaker 1: how they were thought of. I mean, Einstein came up
• 4:10
  Speaker 1: with these right in his equations and it literally just
• 4:13
  Speaker 1: came out in like math first. Yeah, it just came
• 4:15
  Speaker 1: out of the math. You know, you look at the universe,
• 4:18
  Speaker 1: you try to understand how it works. You write down
• 4:20
  Speaker 1: some equations that describe what you see, and then you
• 4:23
  Speaker 1: explore the weird edges of those equations, you say, well,
• 4:26
  Speaker 1: what else could these equations predict what happens in these
• 4:29
  Speaker 1: other weird scenarios? And then you go out and if
• 4:32
  Speaker 1: you believe those equations are real, that they're describing something
• 4:35
  Speaker 1: real about the universe, you go out and check those
• 4:38
  Speaker 1: predictions and see, well, is this just a weird, you know,
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  Speaker 1: figure of math, or is this something that actually happens?
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  Speaker 1: And so it's incredible when you've achieved that, when you
• 4:47
  Speaker 1: really described the universe, You've pulled back a layer of
• 4:50
  Speaker 1: reality and said, here are the fundamental underlying mechanisms, and
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  Speaker 1: I can prove it by showing that I can predict
• 4:56
  Speaker 1: what they do. Do you think Einstein called them black holes?
• 4:59
  Speaker 1: Bread away or what do we call him when he
• 5:01
  Speaker 1: saw him on the on the math page. You know,
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  Speaker 1: he saw these sort of singularities and they he predicted
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  Speaker 1: that light cann't come out of them. Did he have
• 5:08
  Speaker 1: a name for them? Where you're right that the modern
• 5:10
  Speaker 1: idea of black holes certainly came out of Einstein's equations,
• 5:13
  Speaker 1: but the concept of a black hole actually predates Einstein.
• 5:16
  Speaker 1: The idea that you could have an object that had
• 5:19
  Speaker 1: so much gravity that light could not leave it. The
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  Speaker 1: concept of that predated Einstein, so that the phrase black
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  Speaker 1: hole was already sort of existing. Interesting, all right, And
• 5:29
  Speaker 1: we've also now have seen black holes, right, we have
• 5:32
  Speaker 1: pictures of a black hole, that's right. We've known for
• 5:35
  Speaker 1: a while that there are black holes at the centers
• 5:38
  Speaker 1: of galaxies, and we've seen that because we look at
• 5:41
  Speaker 1: the way the things swirl around and the gas and
• 5:44
  Speaker 1: the dust that emit from those galaxies. So you can't
• 5:46
  Speaker 1: see the black hole directly, but you can see the
• 5:48
  Speaker 1: sort of swirling chaos around it, you know, the chaos
• 5:52
  Speaker 1: weasel if you will, of the universe. And we've also
• 5:55
  Speaker 1: seen smaller black holes, black holes that are formed when
• 5:58
  Speaker 1: stars collapse, and we can see those sometimes vie lensing
• 6:02
  Speaker 1: when they pass in front of other stars. So black
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  Speaker 1: holes are amazing and interesting and mysterious, and there are
• 6:09
  Speaker 1: a lot there's a lot about them when we that
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  Speaker 1: we don't know that we don't know what's inside of them.
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  Speaker 1: We don't know how big they can get, and how
• 6:15
  Speaker 1: the ones in the center of galaxies come together. We
• 6:18
  Speaker 1: also sort of don't know how old they are, right,
• 6:21
  Speaker 1: It's hard to tell because they keep so well, that's right,
• 6:24
  Speaker 1: they fit, they are pretty stable, they last a very
• 6:29
  Speaker 1: very long time, and you're right that we don't know
• 6:32
  Speaker 1: so much about when they were made. I mean, one
• 6:34
  Speaker 1: mode of making black holes is you have a star
• 6:37
  Speaker 1: and it collapses and then you have a black hole
• 6:40
  Speaker 1: about the mass of a star or several stars, etcetera.
• 6:42
  Speaker 1: Another is these black holes the very center of galaxies
• 6:45
  Speaker 1: that are millions of suns. But there's the possibility that
• 6:49
  Speaker 1: black holes might even be older than that. They could
• 6:52
  Speaker 1: even be older than the first stars. Really, oh man,
• 6:56
  Speaker 1: I thought black holes only four and from stars. But
• 6:59
  Speaker 1: you're saying it could be older than the ideal starts.
• 7:02
  Speaker 1: That's right. It could be that there were black holes
• 7:04
  Speaker 1: formed before there were even particles. Black holes formed in
• 7:08
  Speaker 1: the very first few moments of the universe predate matter,
• 7:11
  Speaker 1: pre date matter, yes exactly. And so what what what
• 7:15
  Speaker 1: what how could it have anything inside matter didn't exist?
• 7:22
  Speaker 1: I know, we'll dig into it. But these things go
• 7:24
  Speaker 1: by the awesome name of primordial black holes. That is
• 7:28
  Speaker 1: a cool name, all right. So then that's the question
• 7:30
  Speaker 1: for the episode today. Today on the podcast, we'll be
• 7:33
  Speaker 1: tackling the question what are primordial black holes? That it's
• 7:41
  Speaker 1: kind of a hard word to say, but it sounds
• 7:43
  Speaker 1: cool when you say it. Primordial, I know, primordial. It
• 7:46
  Speaker 1: sounds like primeval or something. You know, it sounds like
• 7:49
  Speaker 1: something is crawling out of a swamp somewhere. Yeah, it
• 7:52
  Speaker 1: feels like raw and like unformed and like, oh, my goodness,
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  Speaker 1: predates things. Yeah, it's like from the age of giants. Know,
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  Speaker 1: It's like if Thor had a black hole, it would
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  Speaker 1: be a primordial one where the wild things come from.
• 8:05
  Speaker 1: Kind of exactly. I don't think it's a children's book
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  Speaker 1: primordial black holes, but it's a really cool word. And
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  Speaker 1: it also it touches on that mystery, right we right,
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  Speaker 1: we don't know what happened in the first few moments
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  Speaker 1: of the universe. We don't know how things worked, and
• 8:19
  Speaker 1: so it would be amazing if there were things left
• 8:21
  Speaker 1: over from those very first few moments. That would be fascinating.
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  Speaker 1: So it's kind of a cool concept, and it's it's
• 8:28
  Speaker 1: kind of also kind of a recent concept. I feel like,
• 8:30
  Speaker 1: you know, like Iceland wasn't talking about primordial black holes, right, No,
• 8:34
  Speaker 1: definitely not. This is definitely a more recent concept. So
• 8:37
  Speaker 1: as usually, we were wondering how many people out there
• 8:39
  Speaker 1: had heard of these primorial black holes and or had
• 8:42
  Speaker 1: an idea of what they were. So Daniel went out
• 8:44
  Speaker 1: there into the wilds of the Internet to ask people
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  Speaker 1: what are primorial black holes? That's right, I went out
• 8:50
  Speaker 1: into the primordial Internet, which consists of emailing our listeners
• 8:54
  Speaker 1: and asking them to volunteer to answer spontaneous questions. So
• 8:58
  Speaker 1: thank you to our listeners who participated. If you would
• 9:01
  Speaker 1: like to answer spontaneous questions and here your uninformed speculation
• 9:06
  Speaker 1: on the podcast, please write to questions at Daniel and
• 9:09
  Speaker 1: Jorge dot com. Before you hear these answers, think about
• 9:12
  Speaker 1: it for a second. Have you heard of primordial black holes?
• 9:15
  Speaker 1: Or would you know what to answer if asked this question.
• 9:18
  Speaker 1: Here's what people had to say. I've got nothing on that.
• 9:21
  Speaker 1: I would guess that it's from really early in time,
• 9:24
  Speaker 1: really large black holes. I would guess that it's probably
• 9:27
  Speaker 1: the ones that are at the center of the galaxies,
• 9:30
  Speaker 1: but I'm not sure. Well, like in are the oldest
• 9:34
  Speaker 1: black hole or the first one that was pretty yeah,
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  Speaker 1: maybe one of the biggest black holes in the universe,
• 9:45
  Speaker 1: or yeah, the first ones. Primorial black holes are black
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  Speaker 1: holes that were created by the original plasma of the
• 9:55
  Speaker 1: early universe, before expansion began to occur. As the matter
• 10:01
  Speaker 1: can collapsed and condensed, it became black holes that have
• 10:06
  Speaker 1: persisted since the dawn of time. Basically, I think the
• 10:10
  Speaker 1: black hole at the center of our galaxy is a
• 10:12
  Speaker 1: primordial black hole. Black holes in the center of galaxy
• 10:18
  Speaker 1: the biggest ones. A primordial black hole is a gravitational
• 10:21
  Speaker 1: well created at or just after the initiation of expansion.
• 10:25
  Speaker 1: My understanding is that they consist of mass magnitudes of
• 10:28
  Speaker 1: order larger than supermassive black holes. Perhaps gravitational waves from
• 10:33
  Speaker 1: these primordial black holes leaked through the multiverse and are
• 10:36
  Speaker 1: perceived by us as dark matter primordial black holes. This
• 10:40
  Speaker 1: is really kind of difficult, like, is it the original
• 10:43
  Speaker 1: black hole? Is it what started the big Thing? I
• 10:46
  Speaker 1: have no idea about that. Excited to find out, though
• 10:51
  Speaker 1: primordial black holes are black holes have formed way back
• 10:54
  Speaker 1: at the start of the universe, just after the Big Bang,
• 10:57
  Speaker 1: once inflation had happened and everything else severer pockets of
• 11:00
  Speaker 1: densities left that caused these black holes too to be created,
• 11:05
  Speaker 1: nigrew the hawk and radiation. It's unlikely that any of
• 11:07
  Speaker 1: them still exists. However, they could have caused the start
• 11:10
  Speaker 1: of all the other black holes within the universe. I
• 11:13
  Speaker 1: think black holes that were made during the Big Big Bang.
• 11:19
  Speaker 1: Maybe there they are still older. My guess is that
• 11:24
  Speaker 1: it's a cooler black hole that's like more special than
• 11:27
  Speaker 1: your average ones, so it got its own name. So
• 11:31
  Speaker 1: I think promoting your black holes are black holes have
• 11:34
  Speaker 1: formed shortly after the Big Bang, so that they're really
• 11:39
  Speaker 1: old black holes. But I don't know much more than that.
• 11:42
  Speaker 1: All right, these are pretty good answers. It seems like
• 11:45
  Speaker 1: the word definitely evokes feelings and people, you know, there
• 11:48
  Speaker 1: are like a lot of people say it's before the
• 11:50
  Speaker 1: dawn of time or before the beginning of time. Yeah,
• 11:53
  Speaker 1: the ooze that we walked out of. That was a
• 11:55
  Speaker 1: great answer, And I think that means that this is
• 11:57
  Speaker 1: well named, right, wouldn't you give this high mark? It's
• 12:00
  Speaker 1: like if people could guess what it means. Well, I
• 12:02
  Speaker 1: don't know what they are yet, Daniel, so anything that
• 12:05
  Speaker 1: the judgment is still out, maybe this is a better
• 12:08
  Speaker 1: word for him. I'm feeling a little bit of hesitancy
• 12:10
  Speaker 1: to say anything positive about physics naming, but I'm gonna
• 12:13
  Speaker 1: come back to this at the end of the episode.
• 12:15
  Speaker 1: I see this is the one you would submit to
• 12:17
  Speaker 1: the naming words. This one's high on my list. Yeah
• 12:21
  Speaker 1: you know, I see, we came up with one good name.
• 12:23
  Speaker 1: We're not looking for awards, We're just looking for, you know,
• 12:26
  Speaker 1: to no longer be criticized getting a lot of flak here.
• 12:30
  Speaker 1: He's looking for approval physicity. Want to prove all right,
• 12:35
  Speaker 1: well let's get let's jumb right into it, Daniel. What
• 12:38
  Speaker 1: is the primordial black hole and how is it different
• 12:40
  Speaker 1: than brand new black hole? Yeah, so brand new black
• 12:43
  Speaker 1: holes sort of garden variety black holes that you're familiar with,
• 12:46
  Speaker 1: are the ones formed when stars collapse. You have a
• 12:49
  Speaker 1: big blob of normal matter, you know, quirks and electrons
• 12:54
  Speaker 1: and all sorts of stuff gas and dust, and after
• 12:57
  Speaker 1: it's done fusing, gravity pulls it together. You get this
• 13:00
  Speaker 1: dense spot in space where light cannot escape. So that's
• 13:04
  Speaker 1: your your normal black hole. And the critical thing to
• 13:07
  Speaker 1: making a black hole again is having a very dense
• 13:10
  Speaker 1: blob of matter, so much matter that it's bent space.
• 13:14
  Speaker 1: It's bent space in this way that like the inside
• 13:17
  Speaker 1: of the black hole is cut off from the rest
• 13:19
  Speaker 1: of the universe. It's stretched space in such a way
• 13:22
  Speaker 1: that every path in the black hole goes deeper inside
• 13:26
  Speaker 1: none of them come out, And so you can visualize
• 13:29
  Speaker 1: it as light cannot even escape because the force of
• 13:32
  Speaker 1: gravity is too strong. But the more modern way to
• 13:35
  Speaker 1: think about black holes and gravity is about bending of space.
• 13:38
  Speaker 1: So these things create these weird structures in space that
• 13:42
  Speaker 1: there's no path out of even if you're traveling at
• 13:45
  Speaker 1: the speed of right, it's sort of bend space so
• 13:47
  Speaker 1: much that they kind of form a hole, almost like
• 13:50
  Speaker 1: a hole in space. Yeah, they sort of form a
• 13:52
  Speaker 1: hole in space. You can think of it like the
• 13:54
  Speaker 1: universe has become separated, and there's now this little piece
• 13:57
  Speaker 1: of the universe that there's only a one way door
• 14:00
  Speaker 1: into and once you go in there, you can't come
• 14:02
  Speaker 1: out to the rest of the universe. It's just impossible, right,
• 14:05
  Speaker 1: And like, like you said, it takes a lot to
• 14:07
  Speaker 1: form a black hole. I mean they're so extreme then
• 14:10
  Speaker 1: you know you can't just like it's hard to pack
• 14:12
  Speaker 1: that much mass into such a small space that you know,
• 14:15
  Speaker 1: you need something like a supernova or a star collapsing
• 14:18
  Speaker 1: for that to happen. Yeah, the key thing really is density.
• 14:21
  Speaker 1: You can make small black holes, but you need some
• 14:25
  Speaker 1: very strong force to squeeze the mass into a very
• 14:28
  Speaker 1: small space. The smaller the mass, the smaller the space,
• 14:32
  Speaker 1: and the denser it has to be. And black holes
• 14:34
  Speaker 1: can vary from fairly small masses to enormous masses like
• 14:38
  Speaker 1: millions and millions times the mass of the Sun. Yeah,
• 14:41
  Speaker 1: those are super duper black holes. Yeah, I think that's
• 14:44
  Speaker 1: the official extra califragilistic black holes. Yea, with the spoonful
• 14:50
  Speaker 1: of sugar. And this is the kind of thing we've
• 14:51
  Speaker 1: seen in the universe. We predicted it. We understand the
• 14:54
  Speaker 1: stellar mechanics, we understand the force of gravity, we understand
• 14:57
  Speaker 1: what goes into it. Our numerical similiar makes sense. We've
• 15:01
  Speaker 1: observed them. Everything sort of fits together, right, we can
• 15:04
  Speaker 1: you can see them like floating around in the center
• 15:07
  Speaker 1: of the galaxy. These are like well known. These are
• 15:09
  Speaker 1: well known, the well established. Nobody doubts that these black
• 15:12
  Speaker 1: holes exist. And we've counted them, and they exist at
• 15:15
  Speaker 1: roughly the rate you would expect. And you know, it's
• 15:18
  Speaker 1: a it's an awesome field of study, but one that
• 15:20
  Speaker 1: doesn't have that many surprises in it. But those are
• 15:23
  Speaker 1: stellar black holes. Those are black holes formed from matter
• 15:26
  Speaker 1: that was created after the Big Bang. Right, there's this
• 15:29
  Speaker 1: whole other category of black holes, these primordial black holes
• 15:33
  Speaker 1: that could have been made in the very first few
• 15:36
  Speaker 1: moments of the universe, right, because thanks were pretty crazy
• 15:40
  Speaker 1: at the beginning of the universe. Right, it was like
• 15:42
  Speaker 1: a loud and wild birth for the universe. That's right.
• 15:46
  Speaker 1: It was hot and nasty and wet, and you know,
• 15:48
  Speaker 1: you might think, well, what do you need for making
• 15:51
  Speaker 1: a black hole? You need a dense blob of matter.
• 15:53
  Speaker 1: And you know, early in the universe there was a
• 15:55
  Speaker 1: lot of matter and it was very dense, and so
• 15:58
  Speaker 1: you might expect there to be black holes made in
• 16:01
  Speaker 1: the early universe. It's not that surprising to think that
• 16:04
  Speaker 1: there will be blobs of matter capable of forming black holes. Right.
• 16:08
  Speaker 1: And in fact, this was a listener question we got
• 16:10
  Speaker 1: a while ago about as somebody asked, why doing the
• 16:13
  Speaker 1: universe just collapse into a black hole at the beginning
• 16:15
  Speaker 1: of time? How are we here? Amazing question? It's like,
• 16:20
  Speaker 1: we're here, how come? Right? Because things were so dense
• 16:23
  Speaker 1: at the beginning of time, why didn't it just all
• 16:25
  Speaker 1: collapse into a black hole? That's right. It's a great
• 16:27
  Speaker 1: question because things were really dense and One of the
• 16:30
  Speaker 1: ways we answer that question is that black holes and
• 16:32
  Speaker 1: need to be localized. You can't have the entire universe
• 16:35
  Speaker 1: collapse into a black hole if everything is perfectly smooth.
• 16:38
  Speaker 1: To form black holes, you need hot spots of density.
• 16:42
  Speaker 1: You need to black hole to form somewhere to pick
• 16:45
  Speaker 1: where the black hole forms, You need some spot to
• 16:47
  Speaker 1: be denser than another spot. If everything is equally homogeneous,
• 16:51
  Speaker 1: then the force of gravity just cancels out. It's almost
• 16:53
  Speaker 1: like if you're in a hole. You can't have holes.
• 16:55
  Speaker 1: You can't have a hole in a hole. It kind
• 16:58
  Speaker 1: of is that kind of kind of the idea, like
• 17:00
  Speaker 1: either everything's a hole or you only have little holes.
• 17:03
  Speaker 1: You can't have everything to be a whole because you
• 17:04
  Speaker 1: need extra gravity in one spot. And if everything is smooth,
• 17:07
  Speaker 1: then all the gravity cancels out. I mean, imagine a
• 17:10
  Speaker 1: perfectly smooth universe, even if it's filled with infinite matter.
• 17:14
  Speaker 1: There's no gravitational force on you because in every direction
• 17:18
  Speaker 1: the gravitational force is balanced by matter in the other direction.
• 17:22
  Speaker 1: So to create a black hole, you need a very
• 17:24
  Speaker 1: strong force of gravity, and that can only be created
• 17:26
  Speaker 1: by additional density, by extra density by hot spots. If
• 17:31
  Speaker 1: it's totally smooth. It doesn't matter how dense it is.
• 17:33
  Speaker 1: You can't form black holes, right, And so the idea
• 17:35
  Speaker 1: is that during the Big Bang, the whole thing can
• 17:37
  Speaker 1: turn into a black hole. But maybe there are things
• 17:39
  Speaker 1: were so intense that there that there maybe there were
• 17:42
  Speaker 1: hot spots during the Big Bang, the beginning of the
• 17:44
  Speaker 1: Big Bang, and maybe black holes did form, and that
• 17:48
  Speaker 1: in those early moments. Absolutely, and there had to have
• 17:51
  Speaker 1: been hot spots. If there weren't hot spots early on
• 17:53
  Speaker 1: in the universe, we wouldn't be here either, because the
• 17:56
  Speaker 1: universe is no longer perfectly smooth, right. A perfect smooth
• 18:00
  Speaker 1: universe stays perfectly smooth wherever there's no way to disrupt it.
• 18:04
  Speaker 1: So there had to have been hot spots, and those
• 18:07
  Speaker 1: hot spots seeded the formation of the universe and the
• 18:10
  Speaker 1: structure of the universe as we see it. The reason
• 18:12
  Speaker 1: we have matter here in not a billion light years
• 18:15
  Speaker 1: to the left is because of some hot spot in
• 18:18
  Speaker 1: the early universe which very slowly gathered together matter and
• 18:21
  Speaker 1: formed all this structure or billions of unions. But those
• 18:25
  Speaker 1: same fluctuations, which came from quantum randomness at the tiny scale,
• 18:29
  Speaker 1: could also have generated black holes. Right, that's exactly what
• 18:33
  Speaker 1: you need for a black holes, like an extra little
• 18:34
  Speaker 1: spot of density. And so it's natural the things that
• 18:37
  Speaker 1: you could have also gotten black holes formed in those
• 18:40
  Speaker 1: early moments when you have those hot spots of density
• 18:43
  Speaker 1: and and we're talking like the first few like you know,
• 18:47
  Speaker 1: bazillions of a second after the Big Bang. Yeah, exactly,
• 18:50
  Speaker 1: this is before you had a chance to even make matter. Right,
• 18:53
  Speaker 1: It's not like a question of is the matter made
• 18:55
  Speaker 1: out of corks or electrons? There's just hot stuff, right,
• 18:58
  Speaker 1: There is no matter at all. There's just like energy,
• 19:01
  Speaker 1: crazy energy density. We don't even really know what was there.
• 19:05
  Speaker 1: But yeah, this is very very early on in the
• 19:07
  Speaker 1: beginning of the universe, before even matter, what was cool,
• 19:11
  Speaker 1: before matter even existed. And so then you can ask
• 19:14
  Speaker 1: the fun question like, well of a black hole formed
• 19:16
  Speaker 1: before or matter, like what's in it? Right? What's it
• 19:21
  Speaker 1: made out of? What kind of stuff is there? Right?
• 19:23
  Speaker 1: How can it have anything inside of it? Well, we
• 19:25
  Speaker 1: don't know what it's made out of. It's made out
• 19:27
  Speaker 1: of whatever was in the early universe, which is unfortunately
• 19:31
  Speaker 1: still a huge mystery, like what was creating the inflation
• 19:35
  Speaker 1: of the universe. This grand expansion that stretched out these
• 19:38
  Speaker 1: tiny quantum mechanical fluctuations into larger fluctuations that gravity could
• 19:43
  Speaker 1: begin to see. We don't know, and so we don't
• 19:47
  Speaker 1: know if these black holes were made and what masses
• 19:49
  Speaker 1: they were made at, and what's in them. But it's
• 19:52
  Speaker 1: a huge mystery. You know, we don't even know what's
• 19:54
  Speaker 1: inside current black holes. Like if you take a star
• 19:57
  Speaker 1: and you squish all this stuff together to make a
• 20:00
  Speaker 1: black hole, are their corks in there still? Are they
• 20:03
  Speaker 1: turned into something else? Weird? Like what's going on inside there?
• 20:07
  Speaker 1: It's one of the deepest mysteries of the universe. So
• 20:10
  Speaker 1: if you take a spoonful of like weird early universe
• 20:13
  Speaker 1: stuff and make a black hole versus a spoonful of like,
• 20:15
  Speaker 1: you know, normal, boring, five billion year old star stuff,
• 20:19
  Speaker 1: do you get a different kind of black holes? Not
• 20:21
  Speaker 1: a question we know the answer to. All right, let's
• 20:23
  Speaker 1: get into these primordial black holes. How big they are,
• 20:27
  Speaker 1: what do they look like? And um, what do they
• 20:29
  Speaker 1: smell like? That's what I'm curious about. First, Let's take
• 20:32
  Speaker 1: a quick break, all right, Dannel, we're talking about primorial
• 20:45
  Speaker 1: black holes, and it sounds like the primorial suit kind
• 20:48
  Speaker 1: of well, I don't know what black holes smell like,
• 20:51
  Speaker 1: but these primordial ones are they're probably pretty swampy, you know,
• 20:55
  Speaker 1: in the suit. But you know, that reminds me if
• 20:57
  Speaker 1: you heard of the black hole no hair theorem, what
• 21:01
  Speaker 1: black holes essentially can't have hair, and so if this
• 21:03
  Speaker 1: thing is primoritial and swampy, it's also shaved clean. I'm
• 21:08
  Speaker 1: not making that up. Is a reference to dinosaurs, I'm
• 21:11
  Speaker 1: not making that up. There's a theory that says the
• 21:13
  Speaker 1: only thing that you can know about black holes is
• 21:15
  Speaker 1: their mass, whether they're spinning and they're total electric charge.
• 21:19
  Speaker 1: That's like the only properties they can have. You can
• 21:22
  Speaker 1: know nothing else about what's going on inside of it,
• 21:24
  Speaker 1: what matter is made to use it, whether it shaves
• 21:27
  Speaker 1: daily or you know, lets it self go hairy. And
• 21:30
  Speaker 1: I think that's why they call it the no hair theorem. Oh,
• 21:32
  Speaker 1: I see, It's like we we only know the bare
• 21:34
  Speaker 1: minimum and things like hair, we can't know those details
• 21:37
  Speaker 1: that that's right, we know the bare minimum, and that's
• 21:39
  Speaker 1: all the information that exists. You know. One question is
• 21:42
  Speaker 1: like is there information inside the black hole about what
• 21:45
  Speaker 1: was made? Or is that all the information that exists?
• 21:48
  Speaker 1: And somehow the black holes who just like remove that
• 21:50
  Speaker 1: information from the universe. But that's a topic of another party.
• 21:53
  Speaker 1: And they're just born bald who knows, right, But all right,
• 21:57
  Speaker 1: so they're at the very beginning of the universe, in
• 22:00
  Speaker 1: the very early micro Brazilian seconds of the Big Bang,
• 22:04
  Speaker 1: there could have been black holes. And so this is
• 22:07
  Speaker 1: this is making me ask so many questions, like, you know,
• 22:10
  Speaker 1: how were they form, what were they made out of?
• 22:12
  Speaker 1: How can you have a Can you have a black
• 22:13
  Speaker 1: hole without any matter being around? Do they just have
• 22:16
  Speaker 1: pure energy inside of them? Yeah? Because you know, gravity
• 22:19
  Speaker 1: is linked to energy density. We think of gravity is
• 22:23
  Speaker 1: connected to mass, but really it's connected to energy density,
• 22:25
  Speaker 1: and mass is just one example of how you can
• 22:28
  Speaker 1: store energy. So you can make a black hole just
• 22:31
  Speaker 1: out of super intense radiation, right, as long as you
• 22:35
  Speaker 1: have enough energy density. It's energy density that bends space,
• 22:38
  Speaker 1: that creates what we call gravity. And so it doesn't
• 22:41
  Speaker 1: matter what kind of mass or energy it is, it's
• 22:43
  Speaker 1: just energy density, and it has it has to be
• 22:45
  Speaker 1: more dense than the things around it, right, Yes, exactly,
• 22:49
  Speaker 1: can just be like um, like having enough energy, it's
• 22:52
  Speaker 1: like yet to have more energy than what's around you.
• 22:54
  Speaker 1: So that you can bend space enough to make these pockets. Yeah, exactly,
• 22:57
  Speaker 1: because if there's also energy around you de bens based
• 23:01
  Speaker 1: the opposite way, then you don't get the curvature you need.
• 23:04
  Speaker 1: And one thing that's really amazing about primordial black holes
• 23:07
  Speaker 1: is that because they don't have to come from stars,
• 23:10
  Speaker 1: you can make them in other ways, which means you
• 23:12
  Speaker 1: can make them in a whole variety of different sizes
• 23:17
  Speaker 1: and flavors. Probably, no, there's the no flavor theor it's equivalent.
• 23:22
  Speaker 1: There's an equivalency there, all right, that's right, they only
• 23:25
  Speaker 1: come in dark chocolate budge. No. Because you don't have
• 23:29
  Speaker 1: to start from the star, you can make black holes
• 23:31
  Speaker 1: that are very very small, like mermordial black holes might
• 23:34
  Speaker 1: be as small as like one billion of Oh wow, alright,
• 23:39
  Speaker 1: so the big Bang is banging and there's fluctuations in
• 23:42
  Speaker 1: the energy there, but it's so intense that suddenly you
• 23:45
  Speaker 1: you can floor you can pop these black holes into existence.
• 23:48
  Speaker 1: And you're saying that they could be really small or
• 23:51
  Speaker 1: they can also be really big. Yeah, it just depends
• 23:54
  Speaker 1: on the mechanism that gives you the energy density. And
• 23:56
  Speaker 1: that's something that's just like wild speculation about one theory
• 24:00
  Speaker 1: had some idea for how the energy density profile looked,
• 24:03
  Speaker 1: and that gives you a bunch of small black holes.
• 24:05
  Speaker 1: Another one thinks the energy density profile look different and
• 24:08
  Speaker 1: that gives you a bunch of big black holes. Another one.
• 24:10
  Speaker 1: Most of them actually think that you get a whole distribution,
• 24:13
  Speaker 1: that if you make small black holes, you should also
• 24:15
  Speaker 1: make big black holes and intermediate black holes down from
• 24:18
  Speaker 1: like one billionth of a kilogram up to like thousands
• 24:22
  Speaker 1: of times the mass of our sun. All right, so
• 24:24
  Speaker 1: these primordial black holes there, they sort of make sense,
• 24:28
  Speaker 1: right because there was a big bang and why not.
• 24:31
  Speaker 1: But we can't just sort of go with there was
• 24:34
  Speaker 1: a big bang and whynot? That sounds like you could
• 24:37
  Speaker 1: used to explain anything. Hey, how came you ate all
• 24:40
  Speaker 1: the cookies? Hey well there was a big bang and
• 24:41
  Speaker 1: dot dot dot the cookie I mean, it just seems
• 24:46
  Speaker 1: so crazy. What was happening then? And you know, why
• 24:49
  Speaker 1: why not form black holes? So we can't just kind
• 24:52
  Speaker 1: of go by what what may do? A cartoon is?
• 24:55
  Speaker 1: Or hey, cham why did you climb out Everest? Well?
• 24:58
  Speaker 1: You know the big bang dot dot dot? Why? All right?
• 25:03
  Speaker 1: I need a T shirt that says that anyway, do
• 25:05
  Speaker 1: you want to hold that podcast? You know, a big Bang?
• 25:08
  Speaker 1: Why not? Sure? If it's about the Big Bang? Were
• 25:11
  Speaker 1: still in the Big Bang? The Biggest still banging? Well, well,
• 25:16
  Speaker 1: what do we think they exist? I guess that is
• 25:17
  Speaker 1: there is there more than just kind of the speculation
• 25:20
  Speaker 1: about what could have been happening back there. Yeah, I mean,
• 25:22
  Speaker 1: it's it's a fun idea. It makes sense that they
• 25:25
  Speaker 1: would exist. But if they do exist, they also might
• 25:28
  Speaker 1: solve a bunch of other problems. And this is a
• 25:31
  Speaker 1: cool way to discover something is to see, you, like
• 25:33
  Speaker 1: I have an idea for what might be out there,
• 25:35
  Speaker 1: and then think about what else it might explain. And
• 25:38
  Speaker 1: if you can sort of wrap up a bunch of
• 25:40
  Speaker 1: other things that we didn't quite understand then and tell
• 25:43
  Speaker 1: a nice story that all clicked together, then that's the
• 25:46
  Speaker 1: best kind of discovery. Oh, I see. We we have
• 25:48
  Speaker 1: these other mysteries in the universe, and so now if
• 25:51
  Speaker 1: we can link them to something like primorial black holes,
• 25:55
  Speaker 1: and it would all make sense. They would all make sense.
• 25:57
  Speaker 1: And one of the biggest mysteries out there the mystery
• 26:00
  Speaker 1: of dark matter. Right, we know that most of the
• 26:04
  Speaker 1: universe is not made out of the stuff that I
• 26:06
  Speaker 1: made out of you're made out of Most of the
• 26:08
  Speaker 1: stuff is not made out of quarks and electrons. If
• 26:11
  Speaker 1: you take the budget of the universe, the energy budget
• 26:14
  Speaker 1: of the universe, only about thirty percent of it is
• 26:16
  Speaker 1: actually matter, most of its dark energy, which is pulling
• 26:19
  Speaker 1: the universe apart. But of that slice that's matter, right,
• 26:23
  Speaker 1: about eight percent of that slice of the whole universe
• 26:28
  Speaker 1: is dark matter, this mysterious form of matter that's holding
• 26:32
  Speaker 1: galaxies together and changing the shape of the universe. But
• 26:36
  Speaker 1: we don't know what it is, right, It's totally different
• 26:38
  Speaker 1: than our kind of matter. That's right. Our matter is
• 26:40
  Speaker 1: made out of atoms, which are made out of quarks
• 26:43
  Speaker 1: and electrons. So we call that baryonic matter because it's
• 26:46
  Speaker 1: made out of these particles that are familiar to us.
• 26:48
  Speaker 1: And what we know is that dark matter is not
• 26:51
  Speaker 1: made out of baryonic matter. It's not made out of
• 26:53
  Speaker 1: quarks in some weird configuration that just makes it invisible
• 26:57
  Speaker 1: and transparent, and so we think maybe it's related to
• 26:59
  Speaker 1: prem audeal black holes. So one candidate for dark matter
• 27:03
  Speaker 1: is primordial black holes, because what dark matter needs to
• 27:06
  Speaker 1: be dark, and black holes are dark. Dark matter needs
• 27:11
  Speaker 1: to be pretty stable because it's stuck around the whole
• 27:13
  Speaker 1: lifetime of the universe. And black holes are pretty stable, right.
• 27:16
  Speaker 1: They last for a very very long time, if not forever,
• 27:21
  Speaker 1: and they're hard to spot, and so they're a good
• 27:23
  Speaker 1: candidate for dark matter all this time, dark matter could
• 27:26
  Speaker 1: just be black holes. It could just be black holes. Yeah,
• 27:29
  Speaker 1: I thought we like ruled that out. Well, people have
• 27:31
  Speaker 1: looked for it, you know, we'll talk about that. But
• 27:33
  Speaker 1: it's a pretty compelling possibility. It was never the number
• 27:36
  Speaker 1: one possibility. People were looking for a weird kind of
• 27:39
  Speaker 1: particle that we call a WHIMP, the weekly interacting massive particle.
• 27:43
  Speaker 1: But you know, that particle sort of had it to
• 27:45
  Speaker 1: day and that's come and gone. We thought it was
• 27:47
  Speaker 1: probably a WHIMP, and we looked for it, we didn't
• 27:49
  Speaker 1: see it. And now we're like hunting around in the
• 27:52
  Speaker 1: attic for other ideas of dark matter that might also
• 27:55
  Speaker 1: explain it that we didn't look at so carefully the
• 27:57
  Speaker 1: first time around. And now that the wind ideas sort
• 28:01
  Speaker 1: of lost, it shine a little bit more like digging
• 28:03
  Speaker 1: through the attic to find these other ideas and buff
• 28:05
  Speaker 1: the al Right, So maybe like dark matter is just
• 28:08
  Speaker 1: a bunch of black holes floating around in space, that's right,
• 28:11
  Speaker 1: And they would have to be primordial black holes, not
• 28:14
  Speaker 1: stellar black hole, because we know they've been around for
• 28:16
  Speaker 1: a long time. Yeah, because we know they've been around
• 28:18
  Speaker 1: for a long time. And also we know a lot
• 28:20
  Speaker 1: about how many quarks there were in the very early universe. Right,
• 28:25
  Speaker 1: We know that dark matter is not made out of
• 28:27
  Speaker 1: quarks because we know a lot about how many quarks
• 28:30
  Speaker 1: there were, because we do these really careful calculations, and
• 28:32
  Speaker 1: we see that if you had more quarks or less quirks,
• 28:36
  Speaker 1: you get a different mixture of stuff in the universe,
• 28:38
  Speaker 1: like more helium or more lithium or more hydrogen. And
• 28:41
  Speaker 1: that's the kind of thing we can measure really really well.
• 28:44
  Speaker 1: And then we can backpropagate and we say, all right,
• 28:46
  Speaker 1: given that we know how much helium and lithium and
• 28:48
  Speaker 1: nitrogen and neon there is in the universe, that means
• 28:51
  Speaker 1: there was a certain density of quarks in the early universe.
• 28:54
  Speaker 1: So for dark matter to have been around then, it
• 28:58
  Speaker 1: can't have been made out of quarks. It had to
• 29:00
  Speaker 1: be like taken out of the equation before quarks, right,
• 29:03
  Speaker 1: And that's why I would have to be primordial black holes,
• 29:06
  Speaker 1: So sort of like scoop all that energy in that
• 29:08
  Speaker 1: matter out of the pie before you got around to
• 29:11
  Speaker 1: make it, put it into these primordial black holes, and
• 29:15
  Speaker 1: then wait until humans are confused about the whole thing.
• 29:21
  Speaker 1: Interesting exactly, And so nobody's seen these things, right, primordial
• 29:25
  Speaker 1: black holes still theoretical, nobody has seen them. We'll talk
• 29:28
  Speaker 1: in a minute about how you could look for them.
• 29:30
  Speaker 1: All right, so then what what else do they do
• 29:32
  Speaker 1: they explain? Possibly, well, the other thing they might explain
• 29:35
  Speaker 1: are these incredible black holes at the center of galaxies,
• 29:39
  Speaker 1: you know, the milky Way. It's very core is really
• 29:41
  Speaker 1: hot and dense in the stellar environment there is choked
• 29:44
  Speaker 1: with gas and dust and activity. But at the very
• 29:47
  Speaker 1: very core is a huge black hole. And that black
• 29:50
  Speaker 1: hole is called Sagittarius A, and it has you know,
• 29:54
  Speaker 1: the mass of millions of suns. It's enormous. It's like
• 29:58
  Speaker 1: an incredible object. And they're a big mystery because they're
• 30:01
  Speaker 1: so big. There's sort of like no way for them
• 30:04
  Speaker 1: to have come from stars almost right, Like it's like
• 30:08
  Speaker 1: to cramp together a billion stars that turn into black
• 30:11
  Speaker 1: holes is kind of hard, and it's a lot harder
• 30:13
  Speaker 1: than you might imagine you might think, well, doesn't the
• 30:15
  Speaker 1: big black hole get really powerful and just suck stuff in?
• 30:18
  Speaker 1: Isn't it sort of like a runaway process. Remember that
• 30:21
  Speaker 1: we are not falling into the center of the galaxy
• 30:24
  Speaker 1: for the same reason that the Earth is not plunging
• 30:26
  Speaker 1: into the Sun and the Moon is not crashing under
• 30:29
  Speaker 1: the Earth, and that's rotation, and you have angular momentum
• 30:32
  Speaker 1: which keeps you from falling in. Even a really strong
• 30:35
  Speaker 1: force of gravity cannot overcome angular momentum and suck stuff in.
• 30:40
  Speaker 1: So a really strong black hole, it's not that easy
• 30:43
  Speaker 1: for it to actually grow. It's mostly pull stuff in
• 30:46
  Speaker 1: into a decreation disk to spin around it really fast,
• 30:49
  Speaker 1: but to actually grow it doesn't happen very quickly. So
• 30:53
  Speaker 1: they do these studies where they say, can I make
• 30:55
  Speaker 1: a milky way with this black hole in it? Let
• 30:57
  Speaker 1: me see it with a couple of little black holes
• 30:59
  Speaker 1: and let it grow. And when they do those calculations,
• 31:02
  Speaker 1: they don't get a big enough black hole like the
• 31:04
  Speaker 1: black hole we get in our simulations are much smaller
• 31:07
  Speaker 1: than the black holes we see in real life. So
• 31:10
  Speaker 1: is the idea then that maybe that black hole center
• 31:13
  Speaker 1: of our galaxy was there at the beginning, like maybe
• 31:17
  Speaker 1: it was there before even matter formed around it. Maybe
• 31:20
  Speaker 1: it was one of these huge primorial black holes, and
• 31:23
  Speaker 1: that's how it started. It started off big, exactly. You
• 31:25
  Speaker 1: gotta seat it with a big black hole, like maybe
• 31:27
  Speaker 1: galaxies were formed around huge primordial black holes, which then
• 31:32
  Speaker 1: gathered together dark matter and all sorts of normal matter
• 31:35
  Speaker 1: around it, seating that sort of structure. And if you
• 31:38
  Speaker 1: start from the big enough black hole, then it's much
• 31:41
  Speaker 1: easier to get to the kind of big supermassive black
• 31:45
  Speaker 1: holes that we see at the centers of galaxies. And
• 31:47
  Speaker 1: the other critical thing to understand is that these supermassive
• 31:50
  Speaker 1: black holes are not new. It's not like they've just formed.
• 31:55
  Speaker 1: We see them because they're very easy to spot because
• 31:57
  Speaker 1: they create intense radiation the form of quasars that we've
• 32:01
  Speaker 1: talked about, some of the brightest things in the universe.
• 32:04
  Speaker 1: We can see them from very far away, which means
• 32:06
  Speaker 1: we see very far back in time, so we know
• 32:09
  Speaker 1: that they were super massive black holes making quasars in
• 32:12
  Speaker 1: the early universe. So not only are they huge, but
• 32:16
  Speaker 1: they've been around a long time. So you know, that's
• 32:19
  Speaker 1: sort of smells like there's something else going on out
• 32:21
  Speaker 1: there in terms of making black holes. That's a wild
• 32:24
  Speaker 1: idea because that would mean that galaxies almost formed because
• 32:28
  Speaker 1: of primordial black holes. You know, like like galaxies form
• 32:32
  Speaker 1: where they were because that's where the primordial black holes were,
• 32:35
  Speaker 1: you know, like they were the pioneers for galaxy. And
• 32:39
  Speaker 1: it makes a lot of sense, right, the seeds of
• 32:41
  Speaker 1: structure of the whole universe come from what happened in
• 32:44
  Speaker 1: those first few moments, and if those first few moments
• 32:47
  Speaker 1: triggered the formation of primordial black holes, then that sort
• 32:50
  Speaker 1: of you know, made the decision, like once you create
• 32:52
  Speaker 1: a primordial black hole is sort of a foregone conclusion
• 32:55
  Speaker 1: that everything else is going to like gather around, and
• 32:57
  Speaker 1: you're not gonna start a whole new party when you
• 32:59
  Speaker 1: already have a big one pumping away. So they almost
• 33:02
  Speaker 1: like where they form determined the shape and the look
• 33:05
  Speaker 1: of the universe. And the thing that I'll never stop
• 33:07
  Speaker 1: being amazed by is that those formations come from random fluctuations,
• 33:12
  Speaker 1: like quantum mechanical randomness in the very early universe, which
• 33:16
  Speaker 1: means that like this randomness determined the structure of our universe.
• 33:20
  Speaker 1: You run the same rules of the physics over and
• 33:23
  Speaker 1: over again, you get a very different universe. I mean,
• 33:26
  Speaker 1: you might still have black holes and galaxies, but you
• 33:28
  Speaker 1: get galaxies in different places. Right, somebody's rolling a die
• 33:31
  Speaker 1: out there and making different universes every time. It's sort
• 33:35
  Speaker 1: of amazing every time, every time. Yeah, you know, there's
• 33:38
  Speaker 1: not that many places in the world where you can
• 33:41
  Speaker 1: see the effects of quantum randomness. Mostly it's just averaged out,
• 33:44
  Speaker 1: you know, the quantum mechanics everywhere, but mostly just sort
• 33:47
  Speaker 1: of balances itself out. It's like almost like we're the
• 33:49
  Speaker 1: evidence of quantum fluctuation. Yes, exactly. If there were quantum fluctuations,
• 33:53
  Speaker 1: there would be no structure at all. So we are
• 33:56
  Speaker 1: all the products of quantum fluctuation. So thank you to
• 33:59
  Speaker 1: quantum fluctuations for having made us, said the quantum physicists
• 34:05
  Speaker 1: made of quantum particles. All right, well, let's get into
• 34:07
  Speaker 1: how why else we think they're there, and and whether
• 34:10
  Speaker 1: or not they're real and whether we can maybe actually
• 34:13
  Speaker 1: see or smell and touch a primordial black hole. But first,
• 34:16
  Speaker 1: let's take another quick break. Right then, we're talking about
• 34:29
  Speaker 1: primordial black holes, and you know, they it sounds like
• 34:32
  Speaker 1: maybe they could explain a lot of mysteries like how
• 34:35
  Speaker 1: the universe formed the way it did and where dark
• 34:37
  Speaker 1: matter comes from them. And so we think they're there
• 34:39
  Speaker 1: because not just because of these series and because they
• 34:42
  Speaker 1: could explain these things, but we're also kind of seeing
• 34:45
  Speaker 1: them kind of in a way, or we're seeing clues
• 34:47
  Speaker 1: that they might exist. Yeah, we see lots of things
• 34:49
  Speaker 1: that are easier to explain if primordial black holes exist,
• 34:53
  Speaker 1: which is sort of very indirect argument, but you know,
• 34:56
  Speaker 1: the kind of thing you want to see if these
• 34:58
  Speaker 1: things are real. And another piece of evidence is that
• 35:01
  Speaker 1: we sort of see more black hole collisions than we expected. Remember,
• 35:06
  Speaker 1: we turned on this incredible device a few years ago
• 35:10
  Speaker 1: called Ligo, which looks for gravitational waves, so kind of
• 35:13
  Speaker 1: shaking of space and time that only happens when incredibly
• 35:17
  Speaker 1: massive objects orbit each other and then collide like black holes.
• 35:21
  Speaker 1: And the thing to understand is when they turned this
• 35:23
  Speaker 1: thing on and they made it powerful, they made it
• 35:26
  Speaker 1: sensitive enough to see this kind of shaking of the universe,
• 35:29
  Speaker 1: they didn't know how often the universe got shook. Like
• 35:32
  Speaker 1: they built this device that could see these waves, but
• 35:34
  Speaker 1: they didn't know if the waves were everywhere or just
• 35:37
  Speaker 1: like once in a million years, right, it was sort
• 35:39
  Speaker 1: of built to listening for black holes crashing into each other,
• 35:43
  Speaker 1: but we had no idea how often that happened. Yeah,
• 35:45
  Speaker 1: And there were calculations all over the place. And the
• 35:47
  Speaker 1: amazing thing is that, you know, they turned this thing
• 35:49
  Speaker 1: on and they found one basically right away, like they
• 35:52
  Speaker 1: were still doing a lot of their calibrations and test
• 35:54
  Speaker 1: run when they saw a golden golden collision come in
• 35:58
  Speaker 1: and like the first weekend, like the best case scenario
• 36:01
  Speaker 1: for science, you know, and so it's like it's it's
• 36:04
  Speaker 1: happening more often than they expected, like like you know,
• 36:08
  Speaker 1: there's black holes crashing all over the place kind of yeah,
• 36:10
  Speaker 1: And what that means is that there are more black
• 36:12
  Speaker 1: holes than they thought in the particular sort of mass
• 36:15
  Speaker 1: range that they can see them. Like they're good at
• 36:18
  Speaker 1: seeing collisions of black holes that are like ten to
• 36:20
  Speaker 1: a hundred times the mass of the sun, and there
• 36:23
  Speaker 1: are more of those than they think. Like you can
• 36:26
  Speaker 1: get black holes about the mass of the sun or
• 36:28
  Speaker 1: five times the mass of the sun, but they get
• 36:30
  Speaker 1: black holes like fifty or a hundred times the mass
• 36:33
  Speaker 1: of the sun. Is not that easy, as we were
• 36:35
  Speaker 1: saying before, because there aren't stars that big and black
• 36:38
  Speaker 1: holes have to merge to make them, and so we're
• 36:41
  Speaker 1: seeing more of those than we would expect, which again suggests, hey,
• 36:45
  Speaker 1: maybe these are primordial black Maybe the universe is littered
• 36:48
  Speaker 1: with them. Yeah, maybe even in our own backyard. There
• 36:52
  Speaker 1: could there could be one here in our Solar system.
• 36:54
  Speaker 1: There could be one in our Solar system. And this
• 36:55
  Speaker 1: is very speculative, but super fun. We did a podcast
• 36:59
  Speaker 1: episode last year or about planet nine, like when you
• 37:02
  Speaker 1: look at the orbit of the outer planets, there's some
• 37:04
  Speaker 1: weird things that we don't understand that are sort of
• 37:07
  Speaker 1: suggestive of another gravitational body out there, something out there
• 37:11
  Speaker 1: that's tugging on these things that's making their orbits a
• 37:14
  Speaker 1: little weird. And it's not conclusive at all, but it
• 37:17
  Speaker 1: sort of makes more sense if you add one more planet. Right,
• 37:20
  Speaker 1: problem is we haven't seen that planet, like where is it?
• 37:23
  Speaker 1: You know, even Pluto we can see. And so one
• 37:27
  Speaker 1: super fun idea is that maybe it's like it's invisible.
• 37:31
  Speaker 1: Maybe it's invisible, like we can feel it, it's affecting
• 37:34
  Speaker 1: the orbit of the other planets in US, but you
• 37:36
  Speaker 1: can't see it. So maybe maybe it's a black hole. Yeah,
• 37:39
  Speaker 1: And maybe it's a small black hole. In this case,
• 37:42
  Speaker 1: to have the right mass, it would have to be
• 37:44
  Speaker 1: really small. I mean, it's still be pretty massive. But
• 37:46
  Speaker 1: we're not talking mass to the Sun. We're talking about
• 37:48
  Speaker 1: an object about the size of a tennis ball, and
• 37:52
  Speaker 1: like that's orbiting our Sun. It's like a black like
• 37:55
  Speaker 1: our Solar system. You're saying could have a tennis ball
• 37:58
  Speaker 1: black hole orbiting around it, like it has planets orbiting
• 38:01
  Speaker 1: around it, exactly, And a black hole that's small would
• 38:05
  Speaker 1: still have enough gravitational power to change the orbits of
• 38:10
  Speaker 1: the planet's enough to tweak them to make that visible
• 38:13
  Speaker 1: from Earth. So if there were such a black hole,
• 38:15
  Speaker 1: this is exactly what it would look like. That doesn't
• 38:18
  Speaker 1: mean it's there, but it's tanted right. And so the
• 38:20
  Speaker 1: idea I guess is that this black hole in our
• 38:22
  Speaker 1: Solar system didn't form like after the Solar system. It
• 38:27
  Speaker 1: almost predates the Solar System and predates you know, matter itself.
• 38:32
  Speaker 1: Like it's maybe the universe is literal with these tennis
• 38:35
  Speaker 1: balls black holes, and we just happened to catch one
• 38:38
  Speaker 1: in our Solar system. Yeah, maybe we should have called
• 38:40
  Speaker 1: them like indigenous black holes because they were here before
• 38:42
  Speaker 1: we got here right there, like, hey, this is my
• 38:44
  Speaker 1: solar system. What are you guys doing setting up camps?
• 38:47
  Speaker 1: This colonizing my part of space. Predates the atoms in
• 38:50
  Speaker 1: the Sun. Yeah, it predates the atoms in the STU exactly.
• 38:54
  Speaker 1: And so it could have been here and just fell
• 38:56
  Speaker 1: into orbit around the Sun. It could have been captured,
• 38:58
  Speaker 1: you know, it could be wandering the universe and then
• 39:00
  Speaker 1: been captured. The zillion possibilities. But it's got stories to tell.
• 39:04
  Speaker 1: And yeah, it's seen the birth of our sources. Yeah,
• 39:08
  Speaker 1: it was, It exists. It has embarrassing baby pictures about
• 39:11
  Speaker 1: our son. It knows you when you were small. All right, Um,
• 39:16
  Speaker 1: so then let's cover really quickly here whether or not
• 39:19
  Speaker 1: these primorial holes are real. I mean, how we seen them?
• 39:23
  Speaker 1: How could we see them? What? What are we doing
• 39:25
  Speaker 1: to confirm their existence? Well, we have not seen any
• 39:28
  Speaker 1: evidence for their existence yet, which is disappointing, except maybe
• 39:31
  Speaker 1: this planet nine, right or you know, indirectly as a
• 39:34
  Speaker 1: reason for the ones at the center of galaxies. Yeah,
• 39:37
  Speaker 1: we we see things that would make more sense if
• 39:40
  Speaker 1: primorial black holes existed, but there could also be other explanations.
• 39:43
  Speaker 1: It's very indirect, but we'd like to do is see
• 39:45
  Speaker 1: them sort of much more directly, see something which has
• 39:48
  Speaker 1: to be a primorial black hole. And this one of
• 39:51
  Speaker 1: the origins of this whole idea was Stephen Hawking thinking
• 39:54
  Speaker 1: about black holes evaporating, and he realized that, you know,
• 39:58
  Speaker 1: black holes might not live forever or they give off
• 40:00
  Speaker 1: this radiation. But the key thing about talking radiation is
• 40:04
  Speaker 1: that the bigger the black hole, the less it radiates.
• 40:07
  Speaker 1: So a super huge black hole, anything bigger than like
• 40:11
  Speaker 1: ten to the twelve ms, will take longer than the
• 40:15
  Speaker 1: age of the universe to evaporate, so they basically live
• 40:18
  Speaker 1: forever because they have so much stuff in them. If
• 40:21
  Speaker 1: so much stuff in them, but as a black hole
• 40:23
  Speaker 1: gets smaller it has much less mass, then it actually
• 40:26
  Speaker 1: radiates more. And so if you're less mass, you radiate more,
• 40:29
  Speaker 1: which means you lose mass, which means you're really even more,
• 40:32
  Speaker 1: which means you lose even more mass. And so black
• 40:36
  Speaker 1: holes around like ten to the ten or ten to
• 40:38
  Speaker 1: the eleven kilograms, they can radiate away and actually disappear
• 40:42
  Speaker 1: on the time scale about a billion years, which helps
• 40:47
  Speaker 1: us because well, wouldn't you like to see a black hole?
• 40:49
  Speaker 1: Dye did not? If I have to wait a billion years. Well,
• 40:53
  Speaker 1: but we're fourteen billion years in, which means if black
• 40:56
  Speaker 1: holes are living about a billion years, then they should
• 40:59
  Speaker 1: be dying all the time. We should be looking around
• 41:01
  Speaker 1: and seeing this happen. So you're saying, we could we
• 41:03
  Speaker 1: could see a black hole dye or what will we see?
• 41:06
  Speaker 1: We would see the like the sputtering, the last few
• 41:09
  Speaker 1: gasps or what. Well, it will not go out with
• 41:11
  Speaker 1: a whimper. Remember, it evaporates more rapidly as it gets
• 41:14
  Speaker 1: to lower mass, so the last few moments are very spectacular.
• 41:18
  Speaker 1: That's when it's radiating even more than it has before.
• 41:21
  Speaker 1: So they would go out in this big flash of
• 41:24
  Speaker 1: light essentially like starts off very gradually, and then it
• 41:27
  Speaker 1: would blow all of its energy in the last moments,
• 41:29
  Speaker 1: you know, in this runaway evaporation. It would be very spectacular.
• 41:32
  Speaker 1: Oh wow, like um, the last gasp of a black hole. Yeah,
• 41:36
  Speaker 1: and it would be very characteristic sort of radiation. And
• 41:39
  Speaker 1: so we've looked for this, and we've sent our satellites
• 41:41
  Speaker 1: out to look in space to see if we can
• 41:43
  Speaker 1: see these kind of flashes. And you might expect to
• 41:46
  Speaker 1: see them sort of like in the edge of the
• 41:47
  Speaker 1: galaxy where it's otherwise dark, but we haven't seen any
• 41:50
  Speaker 1: of them, Like, we know what kind of radiation they
• 41:52
  Speaker 1: would give off, because black holes give off a very
• 41:54
  Speaker 1: particular kind of radiation, this hawking radiation of a certain spectrum,
• 41:58
  Speaker 1: so we would expect to see it in the case
• 42:00
  Speaker 1: of temperature of the black hole at the moment, so
• 42:03
  Speaker 1: it would look like nothing else I see. So is
• 42:06
  Speaker 1: the idea then that, you know, if the universe is
• 42:08
  Speaker 1: littered with primoritial black holes, we should see a whole
• 42:11
  Speaker 1: bunch of them dying all the time. Yeah, that's exactly right.
• 42:13
  Speaker 1: They were all born big bang. But if the last
• 42:15
  Speaker 1: you know, billions of years, we've been around billions of years,
• 42:18
  Speaker 1: and so we should see some of them fuzzing out
• 42:20
  Speaker 1: of existence. But so far we haven't seen. We haven't
• 42:22
  Speaker 1: been seen there. We have not and we've looked pretty
• 42:25
  Speaker 1: carefully and we haven't seen those. So that tells us
• 42:28
  Speaker 1: that if there are primordial black holes sort of a
• 42:31
  Speaker 1: very low mass, you know, less than a billion kilograms,
• 42:34
  Speaker 1: then there aren't very many. We can still have one
• 42:36
  Speaker 1: the size of a tennis ball in our solar system,
• 42:39
  Speaker 1: but maybe it's not common. Yeah, and that have small
• 42:42
  Speaker 1: that's right, and the small ones therefore cannot explain the
• 42:44
  Speaker 1: dark matter in the universe. There's just not enough of them.
• 42:47
  Speaker 1: If they do exist, there's not enough of the small
• 42:49
  Speaker 1: mass ones to explain the dark matter. But you know,
• 42:53
  Speaker 1: maybe there are heavier black holes. Maybe there's really big
• 42:56
  Speaker 1: ones out there, so we have other ways to look
• 42:58
  Speaker 1: for those, or maybe all they of ones already died
• 43:01
  Speaker 1: or something precisely, and so we could look around to
• 43:03
  Speaker 1: see if they're heavier mass black holes, and we have
• 43:06
  Speaker 1: other ways to do that. Like if these black holes exist,
• 43:10
  Speaker 1: then we should see lensing effects. We should see them
• 43:12
  Speaker 1: like passing in front of stars and galaxies and and
• 43:16
  Speaker 1: blocking the light from the more, distorting the light from
• 43:19
  Speaker 1: the right, just like dark matter. Wouldn't that account for
• 43:21
  Speaker 1: how dark matter does that? Just like dark matter exactly,
• 43:24
  Speaker 1: except dark matters so far we thought it is more diffused.
• 43:28
  Speaker 1: We've only detected dark matter and like really big effects
• 43:31
  Speaker 1: gravitational effects and big clumps of dark matter lensing background galaxies,
• 43:36
  Speaker 1: for example. What we're looking for here is like micro lensing,
• 43:39
  Speaker 1: like a really tiny spot of something passing in front
• 43:43
  Speaker 1: of an object and distorting it, not a big diffused cloud.
• 43:47
  Speaker 1: If dark matter really is made of primordial black holes.
• 43:49
  Speaker 1: It should be made of these tiny little spots that
• 43:52
  Speaker 1: we can see these micro lensing effects, because I guess
• 43:55
  Speaker 1: you're talking about the black holes now that are about
• 43:57
  Speaker 1: the size of a planet or like giant asteroid. Yeah,
• 44:00
  Speaker 1: giant asteroids or larger, anything larger than that, we should
• 44:04
  Speaker 1: see these lensing effects. And if they're even larger, if
• 44:07
  Speaker 1: they're like really super crazy massive, then they would have
• 44:10
  Speaker 1: big effects on the structure of the galaxy itself and
• 44:13
  Speaker 1: the relationship between galaxies. Like if they were just like ginormous,
• 44:17
  Speaker 1: like mind blowing me, like billions of suns, then they
• 44:20
  Speaker 1: would distort the whole shape of the universe and we
• 44:23
  Speaker 1: would see that for sure. So we know they're not
• 44:25
  Speaker 1: like ridunculously big, and we're pretty sure that there aren't
• 44:29
  Speaker 1: really massive primordial black holes out there because we would
• 44:32
  Speaker 1: see these micro lensing effects. So we've ruled out the
• 44:35
  Speaker 1: very very light ones and the very very very heavy ones.
• 44:38
  Speaker 1: He's this interesting regions sort of in the middle. Well,
• 44:41
  Speaker 1: the very very big ones might be like galaxies, right, like,
• 44:45
  Speaker 1: that's where they might be, right, but we know the
• 44:47
  Speaker 1: size of the black holes in the center of galaxies
• 44:50
  Speaker 1: and that certainly doesn't account for the dark matter. All right,
• 44:52
  Speaker 1: so we're we're looking for them, and um, how are
• 44:55
  Speaker 1: we looking for them? I guess with telescopes, with radio telescopes. Well,
• 44:59
  Speaker 1: another a way to look for them is to see
• 45:01
  Speaker 1: them destroying other stars. Like if you have this sort
• 45:05
  Speaker 1: of intermediate class black holes something like you know, ten
• 45:08
  Speaker 1: of the fourteen ten of the seventeen kilograms, then they
• 45:11
  Speaker 1: would occasionally like pass through a white dwarf or a
• 45:14
  Speaker 1: neutron star and essentially destroy it. What, Yeah, because you
• 45:18
  Speaker 1: know they Yeah, I guess if you have a whole
• 45:20
  Speaker 1: bunch of black holes floating around everywhere, it would be
• 45:23
  Speaker 1: a little bit of you would expect there to be
• 45:25
  Speaker 1: a little bit of a chaos, right, Yeah, it would
• 45:26
  Speaker 1: be disruptive. And so they would pass through and they
• 45:29
  Speaker 1: would shat ot these things. They might ignite fusion and
• 45:31
  Speaker 1: a white dwarf like kick it up into actually burning again,
• 45:35
  Speaker 1: and they could totally disrupt neutron stars. And we just
• 45:37
  Speaker 1: don't see that happening. Like the population of white dwarfs
• 45:40
  Speaker 1: and neutron stars, it looks as we expect, and so
• 45:44
  Speaker 1: we don't see a big effectocy. You know, something assassinating
• 45:47
  Speaker 1: neutron stars out there. We don't see a whole bunch
• 45:49
  Speaker 1: of chaos. Weasels running around the guards balacy. That's right.
• 45:53
  Speaker 1: But this part is very is hard, Like this is
• 45:56
  Speaker 1: a hard measurement to do to find these things, to
• 45:59
  Speaker 1: calculate how often you would see them. So there's sort
• 46:01
  Speaker 1: of a lot of controversy in this middle region here.
• 46:04
  Speaker 1: People are still really not sure how strong those limits.
• 46:07
  Speaker 1: I mean that we had to be these black holes
• 46:09
  Speaker 1: and they would have to run into other stuff, which
• 46:11
  Speaker 1: in space is kind of heart Yeah. And another thing
• 46:13
  Speaker 1: we can do is we can just look at our
• 46:15
  Speaker 1: own son, Like our sun is big enough that it
• 46:18
  Speaker 1: would survive having a small black hole just like go
• 46:21
  Speaker 1: into it. And they've done these awesome studies where they
• 46:24
  Speaker 1: show that you could see it happen by looking at
• 46:27
  Speaker 1: ripples on the surface of the sun, like sun quakes
• 46:31
  Speaker 1: could be evidence of micro black holes entering the Sun
• 46:35
  Speaker 1: like little like would that would be incredible? Wow? Woulduld
• 46:37
  Speaker 1: get into that? Like what happens if a black hole
• 46:39
  Speaker 1: goes into our sun? So it sounds a little disconcerting. Well,
• 46:43
  Speaker 1: if it's really big, then we're in trouble. But if
• 46:45
  Speaker 1: it's small enough, it just sort of like causes literal
• 46:48
  Speaker 1: waves on the surface of the sun. The sun will
• 46:50
  Speaker 1: settle back down and be okay, But you can definitely
• 46:54
  Speaker 1: see that. So that's the kind of thing we're planning
• 46:56
  Speaker 1: to do in the future to see if we can
• 46:58
  Speaker 1: spot these things. All right, Well, it sounds like it
• 47:01
  Speaker 1: sounds like an idea that makes a lot of sense.
• 47:03
  Speaker 1: It's definitely a cool idea. Um, But maybe the jury
• 47:07
  Speaker 1: is still out whether or not they're like actually there,
• 47:10
  Speaker 1: the jury is definitely out. We don't we're looking, Yeah,
• 47:12
  Speaker 1: we're looking. We don't know if these things are real.
• 47:15
  Speaker 1: If they are real, they would explain a lot. But
• 47:17
  Speaker 1: so far, you know that it's not looking good. Like,
• 47:20
  Speaker 1: the best models suggest that if you made primordial black holes,
• 47:24
  Speaker 1: you should make them sort of at all masses, the
• 47:26
  Speaker 1: really small ones, the really big ones, And we haven't
• 47:29
  Speaker 1: seen them at the small masses or the really big ones,
• 47:31
  Speaker 1: so that makes it a little more awkward. So now
• 47:33
  Speaker 1: you have to play some clever game and come up
• 47:35
  Speaker 1: with some reason why you would only make primordial black
• 47:38
  Speaker 1: holes at a certain mass region. So it makes it
• 47:41
  Speaker 1: less fun and sort of less pretty of an idea,
• 47:44
  Speaker 1: But Hey, it's still possible. Yeah, well, yeah, I was
• 47:46
  Speaker 1: getting kind of excited about this idea. It's a preme
• 47:50
  Speaker 1: eval idea. It's primordial. Should I should check my primordial
• 47:54
  Speaker 1: or just all right? Well, I think once again, at
• 47:57
  Speaker 1: this point, I think to all the things we don't
• 47:59
  Speaker 1: know about universe. We don't know what happened at the
• 48:02
  Speaker 1: Big Bang, and we don't know whether or not maybe
• 48:05
  Speaker 1: there are still the remnants of before the Big Bang
• 48:08
  Speaker 1: just hanging out with us. Absolutely, And it's tantalizing to
• 48:13
  Speaker 1: think that those remnants could be here and they could
• 48:15
  Speaker 1: hold clues as to what happened in those first few moments.
• 48:18
  Speaker 1: They could give us insights into how the universe was made.
• 48:21
  Speaker 1: And if we measured the sort of spectrum of these
• 48:24
  Speaker 1: black holes and discovered their masses and only these were made,
• 48:27
  Speaker 1: not those were made, they would really be like a
• 48:30
  Speaker 1: window back in the first few moments of the universe.
• 48:32
  Speaker 1: So I really do hope they do exist, because primordial
• 48:35
  Speaker 1: is a cool word, and the idea is cool, and
• 48:38
  Speaker 1: I hope that they have secrets in them that they
• 48:40
  Speaker 1: will yeah, because you know, why not? Why not? Exactly?
• 48:45
  Speaker 1: The Big Bang was so much fun? Let's do it again,
• 48:48
  Speaker 1: But why not yet? Yeah, let's hold off on that.
• 48:51
  Speaker 1: We'll put a pin on that, all right. Well, we
• 48:54
  Speaker 1: hope you enjoyed that discussion. Thanks for joining us, See
• 48:58
  Speaker 1: you next time. Ye. Thanks for listening and remember that
• 49:08
  Speaker 1: Daniel and Jorge Explain the Universe is a production of
• 49:11
  Speaker 1: I Heart Radio. For more podcast from my Heart Radio,
• 49:15
  Speaker 1: visit the I Heart Radio Apple Apple Podcasts, or wherever
• 49:18
  Speaker 1: you listen to your favorite shows.